:root{
  --brand:#1a56db; --brand-dark:#1e40af; --ink:#1f2937; --muted:#6b7280;
  --bg:#f8fafc; --card:#fff; --line:#e5e7eb; --ok:#059669; --radius:12px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.6;font-size:16px}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:960px;margin:0 auto;padding:0 20px}

/* header */
.site-header{background:var(--card);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:50}
.site-header .container{display:flex;align-items:center;justify-content:space-between;height:62px}
.logo{font-size:22px;font-weight:800;color:var(--brand);letter-spacing:-.5px}
.logo span{color:var(--ink)}
.nav a{margin-left:22px;color:var(--ink);font-weight:500;font-size:15px}

/* hero */
.hero{text-align:center;padding:54px 20px 40px}
.hero h1{font-size:34px;font-weight:800;letter-spacing:-1px;margin-bottom:12px}
.hero p{color:var(--muted);font-size:18px;max-width:620px;margin:0 auto}

/* tool grid */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:18px;padding:10px 0 50px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;
  transition:transform .15s ease,box-shadow .15s ease;display:block}
.card:hover{transform:translateY(-3px);box-shadow:0 8px 24px rgba(0,0,0,.07);text-decoration:none}
.card .ic{font-size:26px}
.card h3{font-size:17px;margin:10px 0 4px;color:var(--ink)}
.card p{font-size:14px;color:var(--muted)}
.card.soon{opacity:.55;pointer-events:none}
.badge{display:inline-block;font-size:11px;background:#eef2ff;color:var(--brand);
  border-radius:20px;padding:2px 9px;margin-top:8px;font-weight:600}

/* search + categories */
.search-wrap{max-width:520px;margin:0 auto 18px;position:relative}
.search-wrap input{width:100%;padding:14px 18px;border:1px solid var(--line);border-radius:30px;
  font-size:16px;background:#fff;box-shadow:0 2px 8px rgba(0,0,0,.04)}
.search-wrap input:focus{outline:none;border-color:var(--brand)}
.cat-title{font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.6px;
  color:var(--muted);margin:30px 0 14px;padding-bottom:9px;border-bottom:1px solid var(--line)}
.cat-block.hidden{display:none}
.card.hidden{display:none}
.no-result{text-align:center;color:var(--muted);padding:40px 0;display:none}
.no-result.show{display:block}
.cat-nav{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin:0 auto 26px;max-width:640px}
.cat-nav a{font-size:13px;font-weight:600;color:var(--brand);background:#eef2ff;
  padding:7px 15px;border-radius:20px;transition:all .15s}
.cat-nav a:hover{background:var(--brand);color:#fff;text-decoration:none}
.cat-block{scroll-margin-top:80px}

/* calculator page */
.breadcrumb{font-size:14px;color:var(--muted);padding:18px 0}
.calc-head h1{font-size:28px;font-weight:800;margin-bottom:8px}
.calc-head .lead{color:var(--muted);margin-bottom:24px}
.calc-box{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:26px;margin-bottom:28px}
.field{margin-bottom:16px}
.field label{display:block;font-weight:600;font-size:14px;margin-bottom:6px}
.field input,.field select{width:100%;padding:11px 13px;border:1px solid var(--line);
  border-radius:8px;font-size:15px;background:#fff}
.field input:focus,.field select:focus{outline:none;border-color:var(--brand)}
.row{display:flex;gap:14px}.row .field{flex:1}
.btn{background:var(--brand);color:#fff;border:none;padding:13px 22px;border-radius:8px;
  font-size:16px;font-weight:600;cursor:pointer;width:100%}
.btn:hover{background:var(--brand-dark)}
.result{margin-top:22px;padding:20px;background:#f0f7ff;border:1px solid #d6e6ff;border-radius:10px;display:none}
.result.show{display:block}
.result .big{font-size:30px;font-weight:800;color:var(--brand-dark)}
.result .sub{color:var(--muted);font-size:14px}
.result table{width:100%;margin-top:12px;border-collapse:collapse;font-size:14px}
.result td{padding:6px 0;border-bottom:1px solid #e0ecff}
.result td:last-child{text-align:right;font-weight:600}

/* ad slot */
.ad-slot{background:#f1f3f5;border:1px dashed #cbd2d9;border-radius:8px;color:#9aa5b1;
  text-align:center;padding:18px;font-size:13px;margin:26px 0}

/* article / SEO content */
.article{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:26px;margin-bottom:30px}
.article h2{font-size:21px;margin:18px 0 10px}
.article h2:first-child{margin-top:0}
.article p{margin-bottom:12px;color:#374151}
.article ul{margin:0 0 12px 20px;color:#374151}

/* footer */
.site-footer{background:var(--card);border-top:1px solid var(--line);padding:30px 20px;margin-top:20px}
.site-footer .container{display:flex;justify-content:space-between;flex-wrap:wrap;gap:14px;font-size:14px;color:var(--muted)}
.site-footer a{margin-right:16px;color:var(--muted)}

@media(max-width:560px){
  .hero h1{font-size:27px}.hero p{font-size:16px}
  .row{flex-direction:column;gap:0}
  .nav a{margin-left:14px;font-size:14px}
}